Light emitting device and light emitting device array

ABSTRACT

A light emitting structure includes lower and upper semiconductor layers having different conductive types, and an active layer disposed between the lower and upper semiconductor layers. The light emitting structure is provided on the substrate. A first electrode layer provided on the upper semiconductor layer includes a first adhesive layer and a first bonding layer overlapping each other. A reflective layer is not provided between the first adhesive layer and the first bonding layer.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. §119 to Korean PatentApplication No. 10-2012-0124381, filed in Korea on 5 Nov. 2012, which ishereby incorporated in its entirety by reference as if fully set forthherein.

BACKGROUND

1. Field

Embodiments relate to a light emitting device and a light emittingdevice array including the same.

2. Background

Red, green and blue light emitting diodes (LEDs) exhibiting highluminance and enabling rendering of white light were developed based onthe growth of metal organic chemical vapor deposition and molecular beamepitaxy of gallium nitride (GaN).

Such a light emitting diode (LED) has superior eco-friendliness becauseit does not contain environmentally harmful substances such as mercury(Hg) used in conventional lighting apparatuses such as incandescentlamps or fluorescent lamps, and serves as an alternative to conventionallight sources due to advantages of long lifespan and low powerconsumption. The key factors in competitiveness of such LEDs are torealize high luminance, based on high-efficiency high-power chips andpackaging technologies.

In order to realize high luminance, increase in light extractionefficiency is important. A variety of methods using flip-chipstructures, surface texturing, patterned sapphire substrates (PSSs),photonic crystal techniques, anti-reflective layer structures and thelike are being researched in order to increase light extractionefficiency.

In general, a light emitting device may include a light emittingstructure including a first conductive type semiconductor layer, anactive layer and a second conductive type semiconductor layer, a firstelectrode to supply a first power to the first conductive typesemiconductor layer and a second electrode to supply a second power tothe second conductive type semiconductor layer which are disposed on thesubstrate.

The above references are incorporated by reference herein whereappropriate for appropriate teachings of additional or alternativedetails, features and/or technical background.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will be described in detail with reference to thefollowing drawings in which like reference numerals refer to likeelements wherein:

FIG. 1 is a sectional view illustrating a light emitting deviceaccording to an embodiment;

FIGS. 2A to 2F are views illustrating embodiments of part “A” of FIG. 1;

FIG. 3 is a sectional view illustrating a light emitting device arrayusing the light emitting device according to the embodiment;

FIG. 4 is a sectional view illustrating a light emitting device arrayaccording to another embodiment;

FIG. 5 is a sectional view illustrating a light emitting device arrayaccording to still another embodiment;

FIG. 6 is a sectional view illustrating a light emitting device arrayaccording to still another embodiment;

FIG. 7 is a plan view illustrating a light emitting device arrayaccording to still another embodiment;

FIG. 8 is a sectional view taken along line 8-8′ of the light emittingdevice array shown in FIG. 7;

FIG. 9 is a sectional view taken along line 9-9′ of the light emittingdevice array shown in FIG. 7;

FIG. 10 is a sectional view taken along line 10-10′ of the lightemitting device array shown in FIG. 7;

FIG. 11 is a sectional view taken along line 11-11′ of the lightemitting device array shown in FIG. 7;

FIG. 12 is a circuit diagram illustrating the light emitting devicearray shown in FIG. 7;

FIG. 13 is a sectional view illustrating a light emitting device arrayincluding the light emitting device according to still anotherembodiment;

FIG. 14 is an exploded perspective view illustrating a lighting deviceincluding a light emitting device package according to an embodiment;and

FIG. 15 is a view illustrating a display device including a lightemitting device package according to an embodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments will be described with reference to the annexeddrawings for better understanding. However, the embodiments may beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein. Rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the disclosure to those skilled in the art.

Prior to description of the embodiments, with regard to description ofpreferred embodiments, it will be understood that, when one element isreferred to as being formed “on” or “under” another element, the oneelement may be directly formed “on” or “under” the another element, orbe indirectly formed “on” or “under” the another element via anintervening element present therebetween. When an element is referred toas being “on” or “under”, “under the element” as well as “on theelement” may be included based on the element.

In the drawings, the thickness or size of each layer is exaggerated,omitted, or schematically illustrated for convenience of description andclarity. In addition, the size or area of each constituent element doesnot entirely reflect the actual size thereof.

FIG. 1 is a sectional view illustrating a light emitting device 100according to an embodiment.

The light emitting device 100 exemplarily shown in FIG. 1 includes asubstrate 10, a buffer layer 12, a light emitting structure 20, firstand second electrode layers 30 and 40, and a conductive layer 50 a.

The substrate 10 may be formed using a carrier wafer suitable for growthof semiconductor materials. In addition, the substrate 10 may be formedof a material having superior thermal conductivity or may be aconductive substrate or an insulating substrate. In addition, thesubstrate 10 may be formed of a light-transmitting material and may havea mechanical strength which does not cause bending of the overallnitride light emitting structure 20 and enables efficient division intoseparate chips through scribing and breaking processes. For example, thesubstrate 10 may contain at least one of sapphire (Al2O3), GaN, SiC,ZnO, Si, GaP, InP, Ga2O3, GaAs, or Ge. The substrate 10 may be providedat an upper surface thereof with irregularities.

The buffer layer 12 may be disposed between the substrate 10 and thelight emitting structure 20 and may be formed using a Group III-Velement compound semiconductor. The buffer layer 12 functions to reducelattice constant mismatch between the substrate 10 and the lightemitting structure 20. For example, the buffer layer 12 may contain AlNor undoped nitride, but the disclosure is not limited thereto. Thebuffer layer 12 may be omitted according to the type of the substrate 10and the type of the light emitting structure 20.

The light emitting structure 20 includes a lower semiconductor layer 22,an active layer 24 and an upper semiconductor layer 26 disposed on thebuffer layer 12 in this order. The lower semiconductor layer 22 and theupper semiconductor layer 26 may have different conductive types.

The lower semiconductor layer 22 may be disposed between the bufferlayer 12 and the active layer 24, contain a semiconductor compound, beimplemented by a semiconductor compound such as Group III-V or GroupII-VI compound and may be doped with a first conductive type dopant. Forexample, the lower semiconductor layer 22 may contain at least one of asemiconductor material having an empirical formula of AlxInyGa(1-x-y)N(0≦x≦z, 0≦y≦1, 0≦x+y≦1), InAlGaN, AlGaAs, GaP, GaAs, GaAsP, or AlGaInP.The lower semiconductor layer 22 may be a first conductive typesemiconductor layer. When the lower semiconductor layer 22 is an n-typesemiconductor layer, the first conductive type dopant may include ann-type dopant such as Si, Ge, Sn, Se or Te. The lower semiconductorlayer 22 may have a single or multiple layer structure, but thedisclosure is not limited thereto.

The active layer 24 may be disposed between the lower semiconductorlayer 22 and the upper semiconductor layer 26 and may have at least oneof a single well structure, a double heterostructure, a multiple wellstructure, a single quantum well structure, a multi quantum well (MQW)structure, a quantum dot structure, or a quantum wire structure. Theactive layer 24 may be formed to have a pair structure including a welllayer and a barrier layer using a Group III-V compound semiconductormaterial, for example, at least one of InGaN/GaN, InGaN/InGaN,GaN/AlGaN, InAlGaN/GaN, GaAs(InGaAs)/AlGaAs, or GaP(InGaP)/AlGaP, butthe disclosure is not limited thereto. The well layer may be formed of amaterial having a smaller energy band gap than an energy band gap of thebarrier layer.

The upper semiconductor layer 26 may be disposed on the active layer 24and contain a semiconductor compound. The upper semiconductor layer 26may be implemented by a Group III-V or Group II-VI compoundsemiconductor or the like, for example, at least one of a semiconductormaterial having an empirical formula of InxAlyGa1-x-yN (0≦x≦1, 0≦y≦1,0≦x+y≦1), AlInN, AlGaAs, GaP, GaAs, GaAsP, or AlGaInP.

Unlike the lower semiconductor layer 22 which is the first conductivetype semiconductor layer, the upper semiconductor layer 26 may be asecond conductive type semiconductor layer and be doped with a secondconductive type dopant. When the upper semiconductor layer 26 is ap-type semiconductor layer, the second conductive type dopant may be ap-type dopant such as Mg, Zn, Ca, Sr, or Ba. The upper semiconductorlayer 26 may have a single or multiple layer structure, but thedisclosure is not limited thereto.

The lower semiconductor layer 22 may be implemented by an n-typesemiconductor layer and the upper semiconductor layer 26 may beimplemented by a p-type semiconductor layer. Accordingly, the lightemitting structure 20 may include at least one of n-p, p-n, n-p-n, orp-n-p junction structures. Meanwhile, the first electrode layer 30 isdisposed on the upper semiconductor layer 26 and the second electrodelayer 40 is disposed on the lower semiconductor layer 22. In order todispose the second electrode layer 40 on the lower semiconductor layer22, the light emitting structure 20 may expose a part of the lowersemiconductor layer 22. That is, a part of the lower semiconductor layer22 may be exposed by etching parts of the upper semiconductor layer 26,the active layer 24 and the lower semiconductor layer 22 through mesaetching. In this case, an exposed surface of the lower semiconductorlayer 22 may be disposed lower than the lower surface of the activelayer 24.

FIGS. 2A to 2F are views illustrating embodiments of part “A” of FIG. 1.

Referring to FIG. 2A, the first electrode layer 30 according to anembodiment may include a first adhesive layer 32 and a first bondinglayer 34 which overlap with each other. That is, the first adhesivelayer 32 is disposed on the upper semiconductor layer 26 and the firstbonding layer 34 is disposed on the first adhesive layer 32. In thiscase, a reflective layer is not interposed between the first adhesivelayer 32 and the first bonding layer 34. That is, the first electrodelayer 30 does not include a reflective layer.

The first adhesive layer 32 may contain a material which ohmic-contactsthe upper semiconductor layer 26. For example, the first adhesive layer32 may be formed with a single or multilayer structure using at leastone material of Cr, Rd, or Ti. In addition, a thickness (T1) of thefirst adhesive layer 32 may be at least 5 nm to 15 nm. For example, whenthe thickness (T1) of the first adhesive layer 32 is less than 2 nm,adhesive strength may be deteriorated and when the thickness (T1)exceeds 15 nm, electric resistance may be increased. Accordingly, thethickness (T1) of the first adhesive layer 32 may be 2 nm to 10 μm.

In addition, the first bonding layer 34 may be disposed such that thefirst bonding layer 34 contacts the first adhesive layer 32. When afirst barrier layer 36 is disposed between the first bonding layer 34and the first adhesive layer 32, as described below, the first bondinglayer 34 may be disposed in an upper part of the first adhesive layer32, instead of contacting the first adhesive layer 32. The first bondinglayer 34 may contain Au. For example, when a thickness (T2) of the firstbonding layer 34 is less than 100 nm, it may be difficult to performwire bonding, and when the thickness (T2) exceeds 2,000 nm, conductiveefficiency may be insufficient in consideration of high cost of Au.Accordingly, the thickness (T2) of the first bonding layer 34 may be 100nm to 2,000 nm, for example, 140 nm.

When a width W1 of the first electrode layer 30 is smaller than 1 μm, itis difficult to implement the first electrode layer 30, and when thewidth W1 exceeds 100 μm, the first electrode layer 30 absorbs light,thus deteriorating light extraction efficiency. Accordingly, the widthW1 of the first electrode layer 30 may be 1 μm to 100 μm, for example, 5μm to 100 μm.

In another embodiment, as exemplarily shown in FIG. 2B, the firstelectrode layer 30 may further include a first barrier layer 36 disposedbetween the first adhesive layer 32 and the first bonding layer 34. Thefirst barrier layer 36 may be disposed so as to contact both the firstadhesive layer 32 and the first bonding layer 34.

The first barrier layer 36 may be formed of one or multiple layers usingat least one material of Ni, Cr, Ti, or Pt. For example, the firstbarrier layer 36 may be formed of an alloy of Cr and Pt. In addition,the first barrier layer 36 may have a thickness (T3) of 200 nm to 300nm, for example, 250 nm.

The second electrode layer 40 disposed on the lower semiconductor layer22 shown in FIG. 1 may include a second adhesive layer and a secondbonding layer which overlap each other. The second adhesive layer may beformed to have a single or multilayer structure using at least onematerial of Cr, Rd, or Ti, and the second bonding layer may contain Au.

The second adhesive layer and the second bonding layer may have the samestructure and material as those of the first adhesive layer 32 and thesecond bonding layer 34, respectively, but the disclosure is not limitedthereto. That is, as in the first electrode layer 30, the secondelectrode layer 40 may have a structure in which the reflective layer isnot disposed between the second adhesive layer and the second bondinglayer, but may have a structure in which a reflective layer is disposedbetween the second adhesive layer and the second bonding layer. Inaddition, the second electrode layer 40 may have different configurationand material from those of the first electrode layer 30. That is, thesecond electrode layer 40 may include the second adhesive layer and thesecond bonding layer, and the first electrode layer 30 may include thefirst adhesive layer 32, the first barrier layer 36 and the firstbonding layer 34.

In addition, the second electrode layer 40 may further include a secondbarrier layer disposed between the second adhesive layer and the secondbonding layer. The second barrier layer may be disposed such that itcontacts both the second adhesive layer and the second bonding layer.The second barrier layer may be formed to have a single or multilayerstructure using a material containing at least one of Ni, Cr, Ti, or Pt.

The second barrier layer may be formed of the same material as the firstbarrier layer 36, but the disclosure is not limited thereto. That is,the second barrier layer may be disposed between the second adhesivelayer and the second bonding layer, as shown in FIG. 2B, may have thesame configuration as the configuration in which the first barrier layer36 is interposed between the first adhesive layer 32 and the firstbonding layer 36. Alternatively, the second barrier layer may have adifferent thickness and material from those of the first barrier layer36.

For example, the second electrode layer 40 may include the secondadhesive layer, the second barrier layer and the second bonding layer,and the first electrode layer 30 may include the first adhesive layer 32and the first bonding layer 34.

In addition, as shown in FIG. 1, a side surface of the lowersemiconductor layer 22 may be inclined at an inclination angle (θ1) withrespect to the substrate 10, and a side surface of the lowersemiconductor layer 22 adjacent to the exposed lower semiconductor layer22 may be inclined at an inclination angle (θ2) with respect to thesubstrate 10. The inclination angles (θ1 and θ2) may be 30° to 80°. Assuch, when a side surface of the lower semiconductor layer 22 isinclined, extraction efficiency of light emitted from the active layer24 may be improved. However, when the inclination angles (θ1 and θ2) areless than 30°, an area of the active layer 24 may be decreased andluminous efficacy may thus be deteriorated, and when the inclinationangles exceed 80°, light extraction efficiency may not be obtained.Accordingly, the inclination angles (θ1 and θ2) may be 30° to 80°, forexample, 70°.

When a reflective layer is disposed between the first adhesive layer 32and the first barrier layer 36, the reflective layer reflects lightemitted from the active layer 24 and thereby reduces dose of lightabsorbed by the metal of the first electrode layer 30. However, when thereflective layer is disposed between the first adhesive layer 32 and thefirst barrier layer 36, there is a problem in that the first bondinglayer 34 made of Au and the reflective layer made of Al areinter-diffused via the first barrier layer 36 made of Ni interposedtherebetween.

In addition, in order to obtain sufficient reflectivity, the reflectivelayer may commonly have a thickness of 50 nm to 300 nm. Due to presenceof this thick reflective layer, the first adhesive layer 32 is formed toa small thickness of, for example, less than 2 nm, thus reducingadhesive strength between the first electrode layer 30 and the lightemitting structure 20.

However, in the present embodiment, the reflective layer is not disposedbetween the first adhesive layer 32 and the first bonding layer 34. Inaddition, the reflective layer is not disposed between the secondadhesive layer and the second bonding layer. Accordingly, the firstadhesive layer 32 may be formed to a great thickness, corresponding tothe thickness of the reflective layer, thus improving adhesive strengthbetween the first electrode layer 30 and the light emitting structure 20and eliminating the risk of inter-diffusion between the reflective layerand the first bonding layer 34. Accordingly, as described above, in thepresent embodiment, the first adhesive layer 32 may have a greatthickness (T1) of 2 nm or more.

In addition, as shown in FIG. 1, the light emitting device may furtherinclude a conductive layer 50 a disposed between the upper semiconductorlayer 26 and the first electrode layer 30. The conductive layer 50 a ofFIG. 1 is disposed on the upper semiconductor layer 26, but thedisclosure is not limited thereto and the conductive layer 50 a may bedisposed in various arrangements. For example, referring to FIGS. 2C and2D, the conductive layer 50 b may be disposed such that it surrounds anupper part and a side part of the current blocking layer 60.

The conductive layers 50 a and 50 b reduce total reflection and exhibitsuperior light transmittance, thus increasing extraction efficiency oflight emitted from the active layer 24 to the upper semiconductor layer26. The conductive layers 50 a and 50 b may be implemented by a singleor multilayer structure using a transparent oxide-based material havinghigh transmittance at visible light emission wavelengths, for example,at least one of indium tin oxide (ITO), tin oxide (TO), indium zincoxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide(IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide(IGTO), aluminum zinc oxide (AZO), aluminum tin oxide (ATO), galliumzinc oxide (GZO), IrOx, RuOx, RuOx/ITO, Ni, Ag, Au, Ni/IrOx/Au, orNi/IrOx/Au/ITO.

In addition, the light emitting device according to the presentembodiment, as exemplarily shown in FIGS. 2C to 2F, may further includea current blocking layer 60 disposed between the first electrode layer30 and the upper semiconductor layer 26. The current blocking layer 60enables efficient diffusion of carriers directed to the active layer 24from the first electrode layer 30 and contributes to improvement ofluminous intensity of the active layer 24.

The current blocking layer 60 may be formed of a material such assilicon oxide (SiO2) or may have a cavity filled with air.Alternatively, as exemplarily shown in FIG. 2C, the current blockinglayer 60 may be implemented by a distributed Bragg reflector (DBR,hereinafter, referred to as a “first distributed Bragg reflector”; 60 aor 60 b). The distributed Bragg reflector means two or more insulatinglayers having different refractive indexes which are alternatelylaminated so as to improve reflectivity. The first distributed Braggreflectors 60 a and 60 b exemplarily shown in FIG. 2C function both asthe reflective layer not disposed between the first adhesive layer 32and the first bonding layer 34, and as the current blocking layer 60.The first distributed Bragg reflectors 60 a and 60 b can moreefficiently perform the function of the reflective layer since they havea reflectivity of, for example, 98%, higher than a reflectivity of 90%or less of the reflective layer.

As shown in FIG. 2C, a first layer 62 a or 62 b and a second layer 64 aor 64 b with different refractive indexes are alternately laminatedtwice, but the first and second layers may be laminated times more thantwice.

The first layer 62 a or 62 b is a low refractive index layer and forexample includes silicon oxide (SiO2) having a refractive index of 1.4or aluminum oxide (Al2O3) having a refractive index of 1.6. In addition,the second layer 64 a or 64 b is a high refractive index layer and forexample includes silicon nitride (Si3N4) having a refractive index of2.05 to 2.25, titanium nitride (TiO2) having a refractive index of 2 ormore, or Si—H having a refractive index of 3 or more.

In addition, in the first distributed Bragg reflector 60 a or 60 b, eachof the first layer 62 a or 62 b, and the second layer 64 a or 64 b mayhave a thickness of λ/(4n). Here, λ represents a wavelength of lightemitted from the active layer 24 and n represents a refractive index ofthe corresponding layer.

Referring to FIG. 2C, the width W2 of the current blocking layer 60implemented by DBR may be 1 to 10 fold the width W1 of the firstelectrode layer 30.

Hereinafter, a semiconductor device array which emits light using aplurality of light emitting devices each of which corresponds to thelight emitting device described above will be described with referenceto the annexed drawings.

FIG. 3 is a sectional view illustrating a light emitting device array200A using the light emitting device according to the embodiment.

The light emitting device array 200A exemplarily shown in FIG. 3includes a substrate 210, a plurality of light emitting devices D1 andD2, a conductive interconnection layer 170 and a first insulating layer180.

The substrate 210 may be formed using a carrier wafer suitable forgrowth of semiconductor materials. In addition, the substrate 10 may beformed of a material having superior thermal conductivity or may be aconductive substrate or an insulating substrate. In addition, thesubstrate 210 may be formed of a light-transmitting material and mayhave a mechanical strength which does not cause bending of the overallnitride light emitting structures 220 a and 220 b of the light emittingdevices D1 and D2. For example, the substrate 210 may contain at leastone of sapphire (Al₂O₃), GaN, SiC, ZnO, Si, GaP, InP, Ga₂O₃, GaAs, orGe. The substrate 210 may be provided at an upper surface thereof withirregularities.

The plurality of light emitting devices (for example, D1 and D2) may bespaced from one another in a horizontal direction on the substrate 210.As shown in FIG. 3, only two light emitting devices D1 and D2 are shownfor convenience of description, but more than two light emitting devicesmay be disposed in the form shown in FIG. 3 on the substrate 210.

Each of the plurality of light emitting devices D1 and D2 has astructure exemplarily shown in FIG. 1. That is, the first light emittingdevice D1 includes a light emitting structure 220 a, a first electrodelayer 130 a and a second electrode layer 140 a, and the second lightemitting device D2 includes a light emitting structure 220 b, a firstelectrode layer 130 b and a second electrode layer 140 b. The lightemitting structure 220 a or 220 b is the same as the light emittingstructure 20 exemplarily shown in FIG. 1. That is, the light emittingstructure 220 a includes lower and upper semiconductor layers 222 a and226 a having different conductive types and an active layer 224 adisposed between the lower and upper semiconductor layers 222 a and 226a, and the light emitting structure 220 b includes lower and uppersemiconductor layers 222 b and 226 b having different conductive typesand an active layer 224 b disposed between the lower and uppersemiconductor layers 222 b and 226 b. The lower semiconductor layer 222a or 222 b, the active layer 224 a or 224 b and the upper semiconductorlayer 226 a or 226 b are the same as the lower semiconductor layer 22,the active layer 24 and the upper semiconductor layer 26 exemplarilyshown in FIG. 1, respectively. Accordingly, a detailed explanationthereof is omitted.

In addition, the first electrode layers 130 a and 130 b are disposed onthe upper semiconductor layers 226 a and 226 b, respectively, and thesecond electrode layers 140 a and 140 b are disposed on the lowersemiconductor layers 222 a and 222 b, respectively.

The first electrode layers 130 a and 130 b include first adhesive layers132 a and 132 b, first barrier layers 136 a and 136 b and first bondinglayers 134 a and 134 b, respectively. The second electrode layers 140 aand 140 b include second adhesive layers 142 a and 142 b, second barrierlayers 146 a and 146 b and second bonding layers 144 a and 144 b,respectively. The first adhesive layers 132 a and 132 b, the firstbarrier layers 136 a and 136 b, and first bonding layers 134 a and 134 bcorrespond to the first adhesive layer 32, the first barrier layer 36and the first bonding layer 34 exemplarily shown in FIG. 1,respectively. The second adhesive layers 142 a and 142 b, the secondbarrier layers 146 a and 146 b, and the second bonding layers 144 a and144 b correspond to the second adhesive layer, the second barrier layerand the second bonding layer of the second electrode layer 40exemplarily shown in FIG. 1. That is, in the first electrode layers 130a and 130 b, the reflective layer is not interposed between the firstadhesive layer 132 a or 132 b and the first bonding layer 134 a or 134b. In the second electrode layers 140 a and 140 b, a reflective layer isnot interposed between the second adhesive layer 142 a or 142 b, and thefirst bonding layer 144 a or 144 b. Furthermore, the first electrodelayers 130 a and 130 b, and the second electrode layers 140 a and 140 bare the same as the first electrode layer 30 and the second electrodelayer 40 exemplarily shown in FIG. 1, respectively. Accordingly, adetailed explanation thereof is omitted.

Hereinafter, for convenience of description, the first electrode layers130 a and 130 b include the first adhesive layers 132 a and 132 b, thefirst barrier layers 136 a and 136 b, and the first bonding layers 134 aand 134 b, respectively, and the second electrode layers 140 a and 140 binclude second adhesive layers 142 a and 142 b, second barrier layers146 a and 146 b, and second bonding layers 144 a and 144 b,respectively. However, the following description may be equally appliedto the cases in which the first electrode layers 130 a and 130 b includeonly the first adhesive layers 132 a and 132 b, and the first bondinglayers 134 a and 134 b, respectively, and in which the second electrodelayers 140 a and 140 b include only the second adhesive layers 142 a and142 b, and the second bonding layers 144 a and 144 b.

The light emitting device D1 or D2 of FIG. 3 may further include theconductive layer 150 a or 150 b interposed between the light emittingstructure 220 a or 220 b, and the first electrode layer 130 a or 130 b.The conductive layer 150 a or 150 b of FIG. 3 corresponds to theconductive layer 50 a of FIG. 1 and a detailed explanation thereof isthus omitted.

One light emitting device D1 exemplarily shown in FIG. 3 is disposed inthe first region A1 on the substrate 210 and the other light emittingdevice D2 is disposed in the second region A2 on the substrate 210. Thelight emitting devices D1 and D2 are spaced from each other by apredetermined distance (d). For example, the distance (d) is 2 μm to 7μm, for example, 5 μm.

The light emitting device array 200A of FIG. 3 further includes a firstinsulating layer 180. The first insulating layer 180 is disposed betweena plurality of light emitting devices D1 and D2, and the conductiveinterconnection layer 170 and functions to electrically isolate thelight emitting devices D1 and D2 from the conductive interconnectionlayer 170.

Meanwhile, the conductive interconnection layer 170 functions to connecttwo adjacent light emitting devices (for example, D1 and D2) among theplurality of light emitting devices. That is, the conductiveinterconnection layer 170 functions to electrically connect the firstelectrode layer 130 b of one (D2) of two light emitting devices D1 andD2, to the second electrode layer 140 a of the other (D1) of two lightemitting devices D1 and D2. As shown in FIG. 3, the two light emittingdevices D1 and D2 may be electrically connected in serial via theconductive interconnection layer 170, but the disclosure is not limitedthereto. That is, the light emitting devices D1 and D2 may beelectrically connected in parallel via the conductive interconnectionlayer 170.

The conductive interconnection layer 170 includes a third adhesive layer172 and a third bonding layer 174 which overlap each other, and areflective layer is not interposed between the third adhesive layer 172and the third bonding layer 174. The third adhesive layer 172 may beformed to have a single or multilayer structure using at least onematerial of Cr, Rd, or Ti, and the third bonding layer 174 contains Au.

The third adhesive layer 172 and the third bonding layer 174 may havethe same configurations and materials as the first adhesive layer 32 andthe first bonding layer 34 shown in FIG. 1, respectively, or may havedifferent configurations and materials as those of the first adhesivelayer 32 and the first bonding layer 34, respectively.

FIG. 4 is a sectional view illustrating a light emitting device array200B according to another embodiment.

In addition, as exemplarily shown in FIG. 4, the conductiveinterconnection layer 170 may further a third barrier layer 176 whichcontacts an upper part of the third adhesive layer 172 and is disposedbetween the third adhesive layer 172 and the third bonding layer 174.The third barrier layer 174 may be formed to have a single or multilayerstructure using at least one of Ni, Cr, Ti, or Pt.

The third barrier layer 176 may have the same material as or materialdifferent from the first barrier layer 36 of FIG. 2B.

As such, the conductive interconnection layer 170 may have the sameconfiguration and material as the first electrode layer 30 of FIG. 1,but a thickness of the conductive interconnection layer 170 may begreater than that of the first electrode layer 130 b.

In the light emitting device array 200A exemplarily shown in FIG. 3, thefirst electrode layer 130 b, the second electrode layer 140 a and theconductive interconnection layer 170 may be separately formed. On theother hand, in the light emitting device array 200B exemplarily shown inFIG. 4, the conductive interconnection layer 170, the first electrodelayer 130 b and the second electrode layer 140 a may be integratedlyformed.

In the integrated structure exemplarily shown in FIG. 4, the secondelectrode layer 140 a is disposed in the third region A3 and the firstelectrode layer 130 b is disposed in the fourth region A4. Theconductive interconnection layer 170 is disposed in an upper part of thesubstrate 210 at a boundary area S and electrically connects the secondelectrode layer 140 a to the first electrode layer 130 b.

In addition, the light emitting device array 200A of FIG. 3 has onefirst insulating layer 180, while the light emitting device array 200Bof FIG. 4 may further include a second insulating layer 182. The secondinsulating layer 182 is disposed between the first insulating layer 180and the plurality of light emitting devices.

Aside from the differences shown in FIGS. 3 and 4, the light emittingdevice array 200B exemplarily shown in FIG. 4 is the same as the lightemitting device array 200A exemplarily shown in FIG. 3 and a detailedexplanation thereof is thus omitted.

At least one of the first and second insulating layers 180 or 182exemplarily shown in FIGS. 3 and 4 may be a distributed Bragg reflector(hereinafter, referred to as a “second distributed Bragg reflector”).The second distributed Bragg reflectors 180 and 182 may efficientlyperform the function of the reflective layer, as described withreference to the first distributed Bragg reflectors 60 a and 60 b. Inaddition, the second distributed Bragg reflectors 180 and 182 mayinclude an insulating material including first and second layers havingdifferent refractive indexes which are alternately laminated two or moretimes, like the first distributed Bragg reflectors 60 a and 60 b. Thefirst layer of the second distributed Bragg reflectors 180 and 182includes a low refractive index layer, for example SiO2 or Al2O3, andthe second layer is a high refractive index layer, for example, Si3N4,TiO2, or Si—H. In addition, in the second distributed Bragg reflectors180 and 182, each of the first and second layers has a thickness ofλ/(4n).

The material for the second distributed Bragg reflectors 180 and 182 isthe same as or different from that of the first distributed Braggreflectors 60 a and 60 b, and the configuration (for example, number oflamination) and the thickness thereof may be the same as or differentfrom the first distributed Bragg reflectors 60 a and 60 b.

FIG. 5 is a sectional view illustrating a light emitting device array200C according to still another embodiment.

Unlike the light emitting device arrays 200A and 200B shown in FIGS. 3and 4, in the light emitting device array 200C exemplarily shown in FIG.5, the respective light emitting devices D1 and D2 may further includecurrent blocking layers 160 a and 160 b spaced in a horizontal directionfrom the first insulating layer 180 between the upper semiconductorlayers 226 a and 226 b, and the first electrode layers 130 a and 130 b.In this case, the first electrode layers 130 a and 130 b may be disposedsuch that they surround upper and side portions of the current blockinglayers 160 a and 160 b. For example, the first adhesive layers 132 a and132 b may be disposed such that they surround upper and side portions ofthe current blocking layers 160 a and 160 b. As such, the light emittingdevice array 200C of FIG. 5 is the same as the light emitting devicearray 200B of FIG. 4, except that the current blocking layers 160 a and160 b are further disposed and the conductive layers 150 a and 150 b areomitted, and a detailed explanation thereof is thus omitted.

FIG. 6 is a sectional view illustrating a light emitting device array200D according to still another embodiment.

As exemplarily shown in FIG. 6, the light emitting device array 200D mayfurther include the conductive layers 150 a and 150 b between thecurrent blocking layers 160 a and 160 b and the first electrode layers130 a and 130 b. Aside from this feature, the light emitting devicearray 200D of FIG. 6 is the same as the light emitting device array 200Cof FIG. 5 and overlapping features are thus omitted.

The current blocking layers 160 a and 160 b of FIGS. 5 and 6 may includea distributed Bragg reflector (hereinafter, referred to as a “thirddistributed Bragg reflector”). The third distributed Bragg reflectors160 a and 160 b may function both as the reflective layer and as thecurrent blocking layers, as described above with reference to the firstdistributed Bragg reflectors 60 a and 60 b.

The third distributed Bragg reflectors 160 a and 160 b may include aninsulating material including first and second layers having differentrefractive indexes which are alternately laminated two or more times.The first layer of the third distributed Bragg reflectors 160 a and 160b is a low refractive index layer, for example, a SiO2 or Al2O3 layer,and the second layer is a high refractive index layer, for example, aSi3N4, TiO2 or Si—H layer. In addition, in the third distributed Braggreflectors 160 a and 160 b, each of the first and second layers has athickness of λ/(4n).

The material of the third distributed Bragg reflectors 160 a and 160 bmay be the same as or different from that of the first distributed Braggreflector 60 a and 60 b, or the second distributed Bragg reflectors 180and 182, and the configuration (for example, number of lamination offirst/second layers) and the thickness thereof may be the same as ordifferent from those of the first distributed Bragg reflectors 60 a and60 b.

FIG. 7 is a plan view illustrating a light emitting device array 200Eaccording to still another embodiment. FIG. 8 is a sectional view takenalong line 8-8′ of the light emitting device array 200E shown in FIG. 7,FIG. 9 is a sectional view taken along line 9-9′ of the light emittingdevice array 200E shown in FIG. 7, FIG. 10 is a sectional view takenalong line 10-10′ of the light emitting device array 200E shown in FIG.7, and FIG. 11 is a sectional view taken along line 11-11′ of the lightemitting device array 200E shown in FIG. 7.

Referring to FIGS. 7 to 11, the light emitting device array 200Eincludes a substrate 210, a buffer layer 212, a light emitting structure220 divided into a plurality of light emitting regions P1 to Pn (n>1,natural number), the conductive layer 150 a, the first insulating layer180, the first electrode layer 250, the conductive interconnectionlayers 240-1 to 240-m (m≧1, natural number), at least one intermediatepad 262 or 264, and the second electrode layer 140.

The substrate 210, the buffer layer 212 and the light emitting structure220 correspond to the substrate 10, the buffer layer 12 and the lightemitting structure 20 of FIG. 1, respectively, and a detailedexplanation thereof is thus omitted.

The lower semiconductor layer 222 may be implemented as an n-typesemiconductor layer and the upper semiconductor layer 226 may beimplemented as a p-type semiconductor layer. Accordingly, the lightemitting structure 220 may include at least one of n-p, p-n, n-p-n, orp-n-p junction structures.

The light emitting structure 220 includes a plurality of light emittingregions P1 to Pn (n>1, natural number) spaced from one another and aplurality of boundary areas (S). Each boundary area S may be disposedbetween the light emitting regions P1 to Pn (n>1, natural number).Alternatively, the boundary area S may be disposed at a circumference ofeach of the light emitting regions P1 to Pn (n>1, natural number). Theboundary area S may be an exposed portion of the lower semiconductorlayer 222 formed by mesa-etching the light emitting structure 220 inorder to divide the light emitting structure 220 into the plurality oflight emitting regions P1 to Pn (n>1, natural number). Areas of thelight emitting regions P1 to Pn (n>1, natural number) may be identical,but the disclosure is not limited thereto.

The light emitting structure 220 in a single chip may be divided intolight emitting regions P1 to Pn (n>1, natural number) through theboundary area S.

The conductive layer 150 a is disposed on the upper semiconductor layer226 and is the same as the conductive layer 50 a of FIG. 1, and adetailed explanation thereof is thus omitted.

The first insulating layer 180 is the same as the first insulating layer180 exemplarily shown in FIGS. 3 to 6 and includes the seconddistributed Bragg reflector as described above. The second distributedBragg reflector 180 is disposed in the plurality of the light emittingregions P1 to Pn (n>1, natural number) and the boundary area S. Forexample, the second distributed Bragg reflector 180 may cover upper andside parts of the light emitting regions P1 to Pn (n>1, natural number)and may cover the boundary area S.

The second distributed Bragg reflector 180 reflects light emitted fromthe light emitting regions P1 to Pn (n>1, natural number). Accordingly,the second distributed Bragg reflector 180 prevents light emitted fromthe light emitting regions P1 to Pn (n>1, natural number) from beingabsorbed in the second electrode layer 140, the conductiveinterconnection layers 240-1 to 240-n (n>1, natural number) and theintermediate pads 262 and 264. For this reason, in the presentembodiment, luminous efficacy is improved.

Referring to FIGS. 7 and 8, the first electrode layer 250 is disposed onthe upper semiconductor layer 226 in one light emitting region (forexample, P1) among the plurality of light emitting regions P1 to Pn (forexample, n=9). The first electrode layer 250 may contact the uppersemiconductor layer 226 or the conductive layer 150 a. For example, thefirst electrode layer 250 may contact the conductive layer 150 a of thefirst light emitting region (for example, P1) among the light emittingregions connected in serial.

The first electrode layer 250 may include a first pad 252 and a branchedfinger electrode 254 disposed on the second distributed Bragg reflector180. A wire (not shown) to supply a first power is bonded to the firstpad 252 and the branched finger electrode 254 may have at least oneportion 256 which branches from the first pad 252, passes through thesecond distributed Bragg reflector 180 and contacts the conductive layer150 a. The first junction layer 132, the first barrier layer 136 and thefirst bonding layer 134 constituting the first electrode layer 250 arethe same as the first junction layer 32, the first barrier layer 36 andthe first bonding layer 34 shown in FIG. 2B and a detailed explanationthereof is thus omitted. In addition, the first electrode layer 250 mayinclude only the first junction layer 132 and the first bonding layer134.

Referring to FIGS. 7 and 11, the second electrode layer 140 may bedisposed on the lower semiconductor layer 222 in one light emittingregion (for example, P9) among the light emitting regions P1 to Pn (forexample, n=9) and contact the lower semiconductor layer 222. The secondelectrode layer 140 may include a second pad bonded to a wire (notshown) to supply a second power. In the embodiment of FIG. 7, the secondelectrode layer 140 may serve as the second pad. Here, the secondjunction layer 142, the second barrier layer 146 and the second bondinglayer 144 are the same as the first junction layer 32, the first barrierlayer 36 and the first bonding layer 34 shown in FIG. 2B, respectively,and a detailed explanation thereof is thus omitted. In addition, thesecond electrode layer 140 may include only the second junction layer142 and the second bonding layer 144.

The conductive interconnection layers 240-1 to 240-m (for example, m=8)are disposed on the second distributed Bragg reflector 180 andelectrically connect the plurality of light emitting regions P1 to Pn(for example, n=9) in serial. For example, the conductiveinterconnection layers 240-1 to 240-m (for example, m=8) connect theplurality of light emitting regions P1 to P9 in serial from the firstlight emitting region P1 as a starting point, at which the firstelectrode layer 250 is disposed, to the ninth light emitting region P9as an end point at which the second electrode layer 140 is disposed.

The conductive interconnection layers 240-1 to 240-m include a thirdadhesive layer 172, a third barrier layer 176 and a third bonding layer174. Here, the third junction layer 172, the third barrier layer 176 andthe third bonding layer 174 are the same as the first junction layer 32,the first barrier layer 36 and the first bonding layer 34 shown in FIG.2B, respectively, and a detailed explanation thereof is thus omitted. Inaddition, the conductive interconnection layers 240-1 to 240-m mayinclude only the third junction layer 172 and the third bonding layer174.

Each conductive interconnection layer (for example, 240-1) mayelectrically connect the lower semiconductor layer 222 of one lightemitting region P1 of adjacent light emitting regions (for example, P1and P2) to the conductive layer 150 a of the other light emitting region(for example, P2).

In another embodiment, wherein the conductive layer 150 a is omitted,the conductive interconnection layer (for example, 240-1) mayelectrically connect the lower semiconductor layer 222 of one lightemitting region (for example, P1) to the upper semiconductor layer 226of the other light emitting region (for example, P2).

The plurality of light emitting regions P1 to Pn (n>1, natural number)connected to one another in serial, included in the light emittingdevice array 200E are referred to as a first light emitting region to annth light emitting region, in order. That is, the light emitting regionin which the first electrode layer 250 is disposed is referred to as thefirst light emitting region P1 and the light emitting region at whichthe second electrode layer 140 is disposed is referred to as an nthlight emitting region. Here, the “adjacent light emitting regions” maybe a kth light emitting region and a k+1th light emitting region, andthe kth conductive interconnection layer may electrically connect thekth light emitting region to the k+1th light emitting region in serial,in which 1≦k≦(n−1).

That is, the kth conductive interconnection layer may electricallyconnect the lower semiconductor layer 222 of the kth light emittingregion to the upper semiconductor layer 226 or the conductive layer 150a of the k+1th light emitting region.

For example, referring to FIG. 8, the kth conductive interconnectionlayer (for example, k=2) may be disposed in the kth light emittingregion (for example, k=2), the k+1th light emitting region (for example,k=2) and the boundary area S disposed therebetween. The kth conductiveinterconnection layer (for example, 240-2) may have at least one firstportion (for example, 272) which passes through the second distributedBragg reflector 180, and contacts the conductive layer 150 a (or uppersemiconductor layer 226) of the k+1th light emitting region (forexample, P3). A solid-line circle shown in FIG. 7 represents a firstportion 272 of the conductive interconnection layers 240-1 to 240-m (forexample, m=8).

The second distributed Bragg reflector 180 may be disposed between thelight emitting structure 220 and the conductive interconnection layer(for example, 240-2) disposed in the boundary area S.

In addition, the kth conductive interconnection layer (for example,240-2) may have at least one second portion (for example, 274) whichpasses through the second distributed Bragg reflector 180, theconductive layer 150 a, the upper semiconductor layer 226 and the activelayer 224 of the kth light emitting region (for example, P2) andcontacts the lower semiconductor layer 222. A dotted-line circle shownin FIG. 7 represents a second portion 274 of the conductiveinterconnection layers 240-1 to 240-m (for example, m=8).

The second distributed Bragg reflector 180 is disposed between the kthconductive interconnection layer (for example, 240-2) and the conductivelayer 150 a, between the second portion 274 of the kth conductiveinterconnection layer (for example, 240-2) and the upper semiconductorlayer 226, and between the second portion 274 of the kth conductiveinterconnection layer (for example, 240-2) and the active layer 224, andelectrically isolate these layers from one another. That is, the seconddistributed Bragg reflector 180 may serve to electrically isolate theconductive layer 150 a, the upper semiconductor layer 226 and the activelayer 224 of the kth light emitting region (for example, P2) from thekth conductive interconnection layer (for example, 240-2).

In the case of the light emitting device array 200A to 200D exemplarilyshown in FIGS. 3 to 6, in order to form the second electrode layer 140connected to the lower semiconductor layer 222, mesa-etching to exposethe lower semiconductor layer 222 by etching the light emittingstructure 220 is performed. In general, the light emitting region of thelight emitting device decreases in proportion to the mesa-etchedportion.

However, in the light emitting device array exemplarily shown in FIGS. 7to 11, the second portion (for example, 274) of the kth conductiveinterconnection layer (for example, 240-2) may have a hole or groovefilled with an electrode material and, for this reason, the amount ofthe light emitting region lost by the mesa-etching is decreased and, inthe present embodiment, the light emitting area is thus increased.

Referring to FIG. 8, a lower surface 278 of the second portion 274 inthe kth conductive interconnection layer (for example, 240-2) may bedisposed lower than a lower surface 276 of the active layer 224.

Referring to FIGS. 7, 8 and 10, the intermediate pad 262 or 264 isdisposed on the second distributed Bragg reflector 180 in the at leastone light emitting region among the light emitting regions P1 to Pn(n>1, natural number) and is electrically connected to the uppersemiconductor layer 226 or the conductive layer 150 a. The intermediatepad 262 or 264 may provide an area to which a wire is bonded so as tosupply first power.

For example, the intermediate pad 262 or 264 may be disposed on thesecond distributed Bragg reflector 180 in at least one light emittingregion (for example, at least one of P3 or P6), excluding the lightemitting regions (for example, P1 and P9) in which the first electrodelayer 250 and the second electrode layer 140 are disposed, among thelight emitting regions (for example, P2 to P8).

The second distributed Bragg reflector 180 is disposed between theintermediate pad 262 or 264, and the conductive layer 150 a, theintermediate pad 262 is connected to the conductive interconnectionlayer (for example, 240-2) disposed in the same light emitting region(for example, P3), and the intermediate pad 264 may be connected to theconductive interconnection layer (for example, 240-5) disposed in thesame light emitting region (for example, P6).

However, in another embodiment, a portion of the intermediate pad maypass through the second distributed Bragg reflector 180 and be directlyconnected to the conductive layer 150 a. In this case, the intermediatepad and the conductive interconnection layer disposed in the same lightemitting region may or may not be connected to each other.

FIG. 12 is a circuit diagram illustrating the light emitting devicearray 200E shown in FIG. 7. Referring to FIGS. 7 and 12, the lightemitting device array 200E may have a common (−) terminal, for example,one second pad 140, may have two or more (+) terminals, for example, thefirst pad 252 and at least one of intermediate pad 262 or 264.

Accordingly, the light emitting device array 200E includes the pluralityof (+) terminals pads 252, 262 and 264, thus enabling use of variousdriving voltages and light emission at various brightnesses. Forexample, when a driving voltage to drive one light emitting region is3.4V, in the case in which the driving voltage applied to the lightemitting device array 200E is 23.8V, the third to ninth light emittingregions P3 to P9 can be driven by supplying a first power to the firstintermediate pad 262.

In addition, when the driving voltage applied to the light emittingdevice array 200E is 13.6V, sixth to ninth light emitting regions P6 toP9 can be driven by supplying the first power to the second intermediatepad 264.

In addition, when the driving voltage applied to the light emittingdevice array 200E is 30.6V, the first to ninth light emitting regions P1to P9 can be driven by supplying first power to the first pad 252.

As such, in the embodiments, the array may be designed so as to drivethe part or the entirety of the light emitting regions according toapplied driving voltage by supplying the first power to one of theintermediate pad 262 or 264, and the first pad 252.

In addition, when the driving voltage is a high voltage, the lightemitting regions may be provided as the number corresponding to the highvoltage. For example, when the driving voltage to drive one lightemitting region is 4 volts and the driving voltage applied to the lightemitting device array 200E is 200V, the array may be designed so that 50(n=50) light emitting regions are provided.

In addition, the conductive interconnection layers 240-1 to 240-m (m≧1,natural number) point-contact the conductive layer 150 a or the lowersemiconductor layer 222, thus increasing a light emitting area,distributing current and thereby improving luminous efficacy.

The second distributed Bragg reflector 180 prevents absorption and lossof light in the first electrode layer 250, the conductiveinterconnection layers 240-1 to 240-n (n>1, natural number) and theintermediate pad 262 or 264, thereby improving luminous efficacy in theembodiment.

FIG. 13 is a sectional view illustrating a light emitting device array200F including the light emitting device according to still anotherembodiment.

Referring to FIG. 13, the light emitting device array 200F includes asubmount 310, a first metal layer 332, a second metal layer 334, a firstbump unit 310 and a second bump unit 320, and a light emitting devicearray 340.

The light emitting device array of FIG. 13 is an example in which thelight emitting device array 200E shown in FIG. 7 is implemented in aflip-chip form, although embodiments are not limited thereto. In otherembodiments, the light emitting device arrays 200A to 200D may beimplemented in flip-chip form as shown in FIG. 13.

The light emitting device 340 mounts the submount 310. The submount 310may be implemented by a package body, a printed circuit board or thelike, and may have various shapes enabling flip-chip bonding of thelight emitting device 340.

The light emitting device array 340 is disposed on the submount 310 andis electrically connected to the submount 310 via the first bump unit310 and the second bump unit 320. The light emitting device array 340shown in FIG. 13 has the same cross-section as the light emitting devicearray 200E shown in FIG. 11. Accordingly, the same elements are notrepeatedly described.

The submount 310 may be include a resin such as polyphthalamide (PPA), aliquid crystal polymer (LCP) or polyamide9T (PA9T), a metal,photo-sensitive glass, sapphire, a ceramic, a printed circuit board orthe like. However, the material for the submount 310 according to thepresent embodiment is not limited thereto.

The first metal layer 332 and the second metal layer 334 are spaced fromeach other in a horizontal direction on the submount 310. The uppersurface of the submount 310 may face the light emitting device array340. The first metal layer 332 and the second metal layer 334 may becomposed of a conductive metal, for example, aluminum (Al) or rhodium(Rh).

The first bump unit 310 and the second bump unit 320 are disposedbetween the submount 310 and the light emitting device array 340. Thefirst bump unit 310 electrically connects the second electrode layer 140to the first metal layer 332.

The second bump unit 320 may electrically connect any one of the firstelectrode layer 250 and the intermediate pad 262 or 264 to the secondmetal layer 334.

The first bump unit 310 includes a first anti-diffusion adhesive layer312, a first bumper 314 and a second anti-diffusion adhesive layer 316.The first bumper 314 is disposed between the second electrode layer 140and the first metal layer 332. The first anti-diffusion adhesive layer312 is disposed between the second electrode layer 140 and the firstbumper 314 and junctions the first bumper 314 to the second electrodelayer 140. That is, the first anti-diffusion adhesive layer 312 improvesan adhesive strength between the first bumper 314 and the secondelectrode layer 140 and prevents permeation or diffusion of ionscontained in the first bumper 314 through the second electrode layer 140into the light emitting structure 220.

The second anti-diffusion adhesive layer 316 is disposed between thefirst bumper 314 and the first metal layer 332 and junctions the firstbumper 314 to the first metal layer 332. The second anti-diffusionadhesive layer 316 improves adhesive strength between the first bumper314 and the first metal layer 332 and prevents permeation or diffusionof ions contained in the first bumper 314 through the first metal layer332 into the submount 310.

The second bump unit 320 includes a third anti-diffusion adhesive layer322, a second bumper 324, and a fourth anti-diffusion adhesive layer326. The second bumper 324 is disposed between one of the firstelectrode layer 250 and the intermediate pad 262 or 264, and the secondmetal layer 334.

The third anti-diffusion adhesive layer 322 is disposed between any oneof the first electrode layer 250 and the intermediate pad 262 or 264,and the second bumper 324, and junctions the two elements. That is, thethird anti-diffusion adhesive layer 322 improves adhesive strength andprevents permeation or diffusion of ions contained in the second bumper324 through the first electrode layer 250 or intermediate pad 262 or 264into the light emitting structure 220.

The fourth anti-diffusion adhesive layer 326 is disposed between thesecond bumper 324 and the second metal layer 334, and junctions thesecond bumper 324 to the second metal layer 334. The fourthanti-diffusion adhesive layer 326 improves adhesive strength between thesecond bumper 324 and the second metal layer 334, and preventspermeation or diffusion of ions contained in the second bumper 324 intothe submount 310 through the second metal layer 334.

The first to fourth anti-diffusion adhesive layers 312, 316, 322 and 326may contain at least one of Pt, Ti, W/Ti, or Au, or an alloy thereof. Inaddition, the first bump 314 and the second bump 324 may contain atleast one of titanium (Ti), copper (Cu), nickel (Ni), gold (Au),chromium (Cr), tantalum (Ta), platinum (Pt), or tin (Sn).

In the embodiments, absorption and loss of light in the first electrodelayer 250, the conductive interconnection layers 240-1 to 240-n (n>1,natural number) and the intermediate pad 262 or 264 are preventedthrough the second distributed Bragg reflector 180, thereby improvingluminous efficacy.

In the electrode layer and the conductive interconnection layer of thelight emitting device and the light emitting device array including thesame according to the embodiments, a reflective layer is not interposedbetween the bonding layer and the adhesive layer, so that the adhesivelayer can be formed to a great thickness. Therefore, adhesive strengthbetween the electrode layer and the light emitting structure may beimproved and adhesive strength between the conductive interconnectionlayer and the insulating layer may be enhanced, thereby solving problemssuch as product defects and decrease in yield due to a conventional thinadhesive layer, allowing the distributed Bragg reflector disposedinstead of the insulating layer to serve as the reflective layer andthereby improving luminous efficacy.

An array of plural light emitting device packages including the lightemitting device or the light emitting device array according to theembodiment may be mounted on a substrate, and optical members, such as alight guide panel, a prism sheet, a diffusion sheet, etc., may bedisposed on an optical path of the light emitting device packages. Thelight emitting device packages, the substrate and the optical membersmay function as a backlight unit.

In accordance with other embodiments, the light emitting device packageincluding the light emitting device or the light emitting device arraymay be implemented for a display device, an indicating device and alighting system, for example, the lighting system may include a lamp ora streetlight.

FIG. 14 is an exploded perspective view illustrating a lighting deviceincluding the light emitting device package according to the embodiment.Referring to FIG. 14, the lighting device includes a light source 750 toemit light, a housing 700 including the light source 750, a radiator 740to emit heat of the light source 750, and a holder 760 to connect thelight source 750 and the radiator 740 to the housing 700.

The housing 700 includes a socket connector 710 connected to an electricsocket (not shown) and a body member 730 connected to the socketconnector 710 wherein the body member 730 includes a light source 750.The body member 730 may be provided with an air passage hole 720.

The body member 730 of the housing 700 is provided on the surfacethereof with one or a plurality of air passage holes 720. The airpassage holes 720 may be radially arranged in the body member 730 or bedisposed in various arrangements.

The light source 750 includes a plurality of the light emitting devicepackages 752 arranged on a substrate 754. The substrate 754 has a shapeenabling insertion into an opening of the housing 700 and is made of amaterial having high thermal conductivity to transfer heat to theradiator 740 as described below. The light emitting device packages mayinclude the light emitting device or the light emitting device arrayaccording to the afore-mentioned embodiment.

The holder 760 is provided under the light source 750 and may include aframe and another air passage hole. In addition, although not shown,optical members are provided under the light source 750 to diffuse,scatter or converge light emitted from the light emitting device package752 of the light source 750.

FIG. 15 is a view illustrating a display device including the lightemitting device package according to one embodiment.

Referring to FIG. 15, the display device 800 according to thisembodiment includes a bottom cover 810, a reflective plate 820 disposedon the bottom cover 810, light source modules 830 and 835 to emit light,a light guide plate 840 arranged in front of the reflective plate 820and guiding light emitted the light source module toward the front ofthe display device, an optical sheet including a first prism sheet 850and a second prism sheet 860 arranged in front of the light guide plate840, a display panel 870 arranged in front of the optical sheet, animage signal output circuit 872 connected to the display penal 870 andsupplying an image signal to the display panel 870, and a color filter880 arranged in front of the display panel 870. The bottom cover 810,the reflective plate 820, the light source modules 830 and 835, thelight guide plate 840 and the optical sheet may constitute a backlightunit.

The light source module includes a light emitting device package 835mounted on the substrate 830. The substrate 830 may be a PCB or thelike. The light emitting device package 835 may be the same as the lightemitting device or the light emitting device array according to theembodiment.

The bottom cover 810 may accommodate constituent components of thedisplay device 800. The reflective plate 820 may be provided as aseparate element, as illustrated in the drawing, or as a coating havinga high reflectivity provided on the rear surface of the light guideplate 840 or the front surface of the bottom cover 810.

Here, the reflective plate 820 may be made of a highly reflectivematerial which may have an ultrathin structure and examples thereofinclude polyethylene terephtalate (PET).

In addition, the light guide plate 840 is made of polymethylmethacrylate(PMMA), polycarbonate (PC) or polyethylene (PE).

The first prism sheet 850 is formed at one side of a support film usinga light-transmitting and elastic polymer and the polymer may include aprism layer having a plurality of repeatedly formed three-dimensionalstructures. Here, the plurality of patterns, as illustrated in thedrawing, may be provided as stripe patterns in which ridges and valleysrepeatedly alternate.

A direction of the ridges and valleys arranged on one side of thesupport film in the second prism sheet 860 may be vertical to adirection of ridges and valleys arranged on one side of the support filmin the first prism sheet 850 so that light transferred from the lightsource module and the reflective sheet can be uniformly distributed inall directions of the display panel 870.

Although not shown, a diffusion sheet may be disposed between the lightguide plate 840 and the first prism sheet 850. The diffusion sheet maybe made of a polyester or polycarbonate-based material and maximizelight projection angle by refracting and scattering light emitted fromthe backlight unit. In addition, the diffusion sheet includes a supportlayer containing a light diffusion agent and a first layer and a secondlayer which are formed on a light-emission surface (first prism sheetdirection) and a light incidence surface (reflective sheet direction),respectively, and contain no light diffusion agent.

In the present embodiment, the first prism sheet 850 and the secondprism sheet 860 constitute an optical sheet and the optical sheet may beprovided as another combination, for example, a micro lens array, acombination of a diffusion sheet and a micro lens array, or acombination of a prism sheet and a micro lens array.

The display panel 870 may be provided with a liquid crystal panel andthe liquid crystal panel as well as other display devices requiring alight source may be provided.

Embodiments provide a light emitting device to improve yield and provideenhanced luminous efficacy, and a light emitting device array includingthe same.

In one embodiment, a light emitting device includes a substrate, a lightemitting structure including lower and upper semiconductor layers havingdifferent conductive types, and an active layer disposed between thelower and upper semiconductor layers, the light emitting structure beingdisposed on the substrate, and a first electrode layer disposed on theupper semiconductor layer, wherein the first electrode layer includes afirst adhesive layer and a first bonding layer overlapping each other,wherein a reflective layer is not disposed between the first adhesivelayer and the first bonding layer. The first electrode layer may furtherinclude a first barrier layer disposed on the first adhesive layer suchthat the first barrier layer contacts the first adhesive layer.

The light emitting device may further include a second electrode layerdisposed on the lower semiconductor layer, wherein the second electrodelayer includes a second adhesive layer and a second bonding layeroverlapping each other, wherein a reflective layer is not disposedbetween the second adhesive layer and the second bonding layer. Thesecond electrode layer may further include a second barrier layerdisposed on the second adhesive layer such that the second barrier layercontacts the second adhesive layer.

The first or second adhesive layer may include at least one of Cr, Rd,or Ti. The first barrier layer may include at least one of Ni, Cr, Ti,or Pt. The first adhesive layer may have a thickness of at least 2 nm to15 nm. A side surface of the lower semiconductor layer may be inclined.

The light emitting layer may further include a conductive layer disposedbetween the upper semiconductor layer and the first electrode layer andmay further include a current blocking layer disposed between theconductive layer and the upper semiconductor layer. The conductive layermay be disposed to surround upper and side parts of the current blockinglayer.

The current blocking layer may be a distributed Bragg reflector. Thedistributed Bragg reflector may include an insulating material includingtwo or more first and second layers having different refractive indexeswhich are alternately laminated two or more times. The first electrodelayer may have a width of 5 μm to 100 μm.

The first bonding layer may have a thickness of 100 nm to 2,000 nm.

In another embodiment, a light emitting device array includes asubstrate, a plurality of light emitting devices spaced from one anotherin a horizontal direction on the substrate, a conductive interconnectionlayer to connect the two light emitting devices among the plurality oflight emitting devices, and a first insulating layer disposed betweenthe light emitting devices and the conductive interconnection layer,wherein respective light emitting devices include a light emittingstructure including lower and upper semiconductor layers havingdifferent conductive types, and an active layer disposed between thelower and upper semiconductor layers, a first electrode layer disposedon the upper semiconductor layer, and a second electrode layer disposedon the lower semiconductor layer, wherein the conductive interconnectionlayer connects the first electrode layer of one of the two lightemitting devices to the second electrode layer of the other of the twolight emitting devices, wherein the first electrode layer includes afirst adhesive layer and a first bonding layer overlapping each other,wherein a reflective layer is not disposed between the first adhesivelayer and the first bonding layer.

The second electrode layer includes a second adhesive layer and a secondbonding layer overlapping each other, wherein a reflective layer is notdisposed between the second adhesive layer and the second bonding layer.The second electrode layer may further include a second barrier layerdisposed on the second adhesive layer such that the second barrier layercontacts the second adhesive layer.

The conductive interconnection layer may include a third adhesive layerand a third bonding layer overlapping each other, wherein a reflectivelayer is not disposed between the third adhesive layer and the thirdbonding layer.

The conductive interconnection layer may further include a third barrierlayer on the third adhesive layer such that the third barrier layercontacts the third adhesive layer.

The first, second or third adhesive layer may include at least one ofCr, Rd, or Ti. The first, second or third barrier layer may include atleast one of Ni, Cr, Ti, or Pt. The first, second or third adhesivelayer may have a thickness of at least 5 nm to 15 nm.

The light emitting device array may further include a second insulatinglayer disposed between the first insulating layer and the light emittingdevices.

At least one of the first and second insulating layers may be adistributed Bragg reflector.

The first and second electrode layers of the two light emitting devicesconnected through the conductive interconnection layer, and theconductive interconnection layer may be integrated with one another.

A thickness of the conductive interconnection layer may be greater thanthat of the first electrode layer. Each light emitting device mayfurther include a conductive layer disposed between the uppersemiconductor layer and the first electrode layer.

Each light emitting device may further include a current blocking layerspaced from the first insulating layer between the light emittingstructure and the first electrode layer.

The first conductive layer may be disposed to surround upper and sideparts of the current blocking layer and the current blocking layer maybe a distributed Bragg reflector.

The first electrode layer may have a width of 5 μm to 100 μm.

The light emitting devices may be connected in serial through theconductive interconnection layer.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A light emitting device array, comprising: asubstrate; a plurality of light emitting devices spaced from one anotherin a horizontal direction on the substrate; a conductive interconnectionlayer to connect the two light emitting devices among the plurality oflight emitting devices; and a first insulating layer between the lightemitting devices and the conductive interconnection layer, whereinrespective light emitting devices comprise: a light emitting structureincluding lower and upper semiconductor layers having differentconductive types, and an active layer provided between the lower andupper semiconductor layers; a first electrode layer provided on theupper semiconductor layer; and a second electrode layer provided on thelower semiconductor layer, wherein the conductive interconnection layerconnects the first electrode layer of one of the two light emittingdevices to the second electrode layer of the other of the two lightemitting devices, wherein the first electrode layer includes a firstadhesive layer and a first bonding layer overlapping each other, whereina reflective layer is not provided between the first adhesive layer andthe first bonding layer, wherein the conductive interconnection layercomprises a third adhesive layer and a third bonding layer overlappingeach other, and wherein a reflective layer is not disposed between thethird adhesive layer and the third bonding layer.
 2. The light emittingdevice array according to claim 1, wherein the conductiveinterconnection layer further comprises a third barrier layer on thethird adhesive layer such that the third barrier layer contacts thethird adhesive layer.
 3. The light emitting device array according toclaim 1, further comprising a second insulating layer disposed betweenthe first insulating layer and the light emitting devices.
 4. The lightemitting device array according to claim 3, wherein at least one of thefirst and second insulating layers is a distributed Bragg reflector. 5.The light emitting device array according to claim 1, wherein the firstand second electrode layers of the two light emitting devices connectedthrough the conductive interconnection layer, and the conductiveinterconnection layer are integrated with one another.
 6. The lightemitting device array according to claim 1, wherein each light emittingdevice further comprises a conductive layer disposed between the uppersemiconductor layer and the first electrode layer.
 7. The light emittingdevice array according to claim 6, wherein each light emitting devicefurther comprises a current blocking layer spaced from the firstinsulating layer between the light emitting structure and the firstelectrode layer.
 8. A light emitting device array, comprising: asubstrate; a plurality of light emitting devices spaced from one anotherin a horizontal direction on the substrate; a conductive interconnectionlayer to connect the two light emitting devices among the plurality oflight emitting devices; a first insulating layer between the lightemitting devices and the conductive interconnection layer; and a secondinsulating layer disposed between the first insulating layer and thelight emitting devices, wherein respective light emitting devicescomprise: a light emitting structure including lower and uppersemiconductor layers having different conductive types, and an activelayer provided between the lower and upper semiconductor layers; a firstelectrode layer provided on the upper semiconductor layer; and a secondelectrode layer provided on the lower semiconductor layer, wherein theconductive interconnection layer connects the first electrode layer ofone of the two light emitting devices to the second electrode layer ofthe other of the two light emitting devices, wherein the first electrodelayer includes a first adhesive layer and a first bonding layeroverlapping each other, wherein a reflective layer is not providedbetween the first adhesive layer and the first bonding layer, whereinthe conductive interconnection layer comprises a third adhesive layerand a third bonding layer overlapping each other, and wherein areflective layer is not disposed between the third adhesive layer andthe third bonding layer.
 9. The light emitting device array according toclaim 8, wherein at least one of the first and second insulating layersis a distributed Bragg reflector.
 10. A light emitting device array,comprising: a substrate; a plurality of light emitting devices spacedfrom one another in a horizontal direction on the substrate; aconductive interconnection layer to connect the two light emittingdevices among the plurality of light emitting devices; and a firstinsulating layer between the light emitting devices and the conductiveinterconnection layer, wherein respective light emitting devicescomprise: a light emitting structure including lower and uppersemiconductor layers having different conductive types, and an activelayer provided between the lower and upper semiconductor layers; a firstelectrode layer provided on the upper semiconductor layer; and a secondelectrode layer provided on the lower semiconductor layer, wherein theconductive interconnection layer connects the first electrode layer ofone of the two light emitting devices to the second electrode layer ofthe other of the two light emitting devices, wherein the first electrodelayer includes a first adhesive layer and a first bonding layeroverlapping each other, wherein a reflective layer is not providedbetween the first adhesive layer and the first bonding layer, whereinthe conductive interconnection layer comprises a third adhesive layerand a third bonding layer overlapping each other, wherein a reflectivelayer is not disposed between the third adhesive layer and the thirdbonding layer, and wherein each light emitting device further comprisesa conductive layer disposed between the upper semiconductor layer andthe first electrode layer.
 11. The light emitting device array accordingto claim 10, wherein each light emitting device further comprises acurrent blocking layer spaced from the first insulating layer betweenthe light emitting structure and the first electrode layer.